1. Field of the Invention
This invention relates generally to slide fasteners and more particularly to end stop devices therefor.
2. Description of the Prior Art
The slide fastener is provided with a slider reciprocally movable for opening and closing the same, the reciprocal movement of the slider being limited by stop members mounted on the top and bottom ends of the fastener.
There has been proposed a variety of fastener end stops, some being made of metals and others of plastics. Those made of thermoplastic materials to which the invention pertains are typically disclosed for example in Japanese Patent Publication Nos. 48-37421 and 49-36975, in which a piece of thermoplastic film or monofilament is attached by welding thermally or ultrasonically to an inner edge of a slide fastener tape, so that the film, fastener elements and tape yarns are integrally joined together. In the case of slide fasteners with support tapes coated with rubber or other impermeable materials to render the fastener gastight or waterproof, it has been difficult to attach the end stops securely to such tape surfaces against displacement under the influence of severe impinging pressure exerted by the slider where such pressure is greater than with ordinary slide fasteners.
Many attempts have been made to contrive means for anchoring the end stops on fluid-tight slide fasteners against displacement or detachment from the fastener tapes in use. One such atempt was to provide an end stop structure with a peripheral protuberance or fin which because of its flexibility serves to reinforce the positional stability of the end step by damping the impact pressure of the slider, in which instance it was necessary to remove the fin from the front end portion of the end step to avoid jamming with the slider. Tests were made on a number of samples of such end stops that were repeatedly struck by the slider, with the results that most of them became separated from the fastener progressively from where the slider pressure is directed.